Each patient will complete quality of life and performance questionnaires. ILLT will be performed under general anesthetic in a procedure similar to brachytherapy, using transrectal ultrasound to guide insertion of the laser and monitoring probes into the sector containing the cancer as visualized by the MR scan. Following the procedure, patients will be assessed for clinical signs of urinary, rectal, and erectile complications and will complete validated self-assessment tools on these functions. MRI at 7 days and MRI and biopsy at 6 months will be used to assess the extent of tissue effect and presence of cancer due to ILTT. Patients will remain on standard Watchful Waiting surveillance for any further sign of disease progression. ILLT will not restrict any future treatment of prostate cancer.